The best idea is to go to your local branch of Evans (don't go to a small lbs - if you're not going to buy it's noit fair, and Evans have a wider range and are gits anyway
). Try out a selection of bikes, including full-on road bikes, light tourers, and maybe one of the cyclo-cross crossovers like a Kona Jake or a Specialized tricross.
What you're looking for is something that feels more responsive than your current mount (though remember that you're not carrying your luggage, lock etc on the test bike), and yet more comfortable. If it's a harsh ride, you won't enjoy your riding - and it's all about fun, isn't it?
Once you've done some test rides, you will know what suits
you, although you'll probably have a whole load more questions. Come back and ask us, and we'll do our best to answer.
At the end of the day, there is no 'right' answer, and, on a typical yacf ride, you will see an extraordinarily wide range of bikes & trikes. Get something that works for you.